Читать книгу Creating an Eco-Friendly Home & Workplace - Paul Hymers - Страница 25

Lamps are a long way from being white all the time, but then white is not always the colour you want. Apart from the many coloured lamps available, which tend to provide significantly lower illumination, specific types of lamp have unique hues, determined by their colour temperature.

The varying wavelengths in light’s electromagnetic spectrum are interpreted by our brains as colours – red for the longest wavelengths (700 mn) and lowest frequencies, violet at the shortest wavelengths (400 mn) and highest frequencies. The colours of the rainbow fall between them. Outside of those limits, our eyes can’t see the infrared before the red kicks in, or the ultra-violet after the violet drops out. We can, however, feel the heat from infrared light on our skin. The lower the colour temperature, the warmer the light. Take candle light for example. At less than 2000 deg.K, it is edging out of the red and into the orange end of the spectrum. Sunlight on a summer’s day is in the middle of the scale at around 5500 deg.K, but rising up into a blue sky away from sunlight sees the colour temperature increase to 9000 deg.K.